Isolated Gas Heating System for an Electronic Display

ABSTRACT

A preferred embodiment relates to a heating system and a method for heating an electronic display. A preferred embodiment includes a transparent gas heat-transfer chamber which may be coexistent with the viewable display surface. The heating system defines two gas compartments that are anterior and posterior to the electronic display and are in gaseous communication. Fans may be used to propel the isolated gas through the two chambers. The circulating gas transfers heat to the electronic display surface by convection. The isolated gas is preferably transparent or at least semi-transparent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional patent application and claimspriority to U.S. Provisional Application No. 61/076,126 filed Jun. 26,2008; 61/057,599 filed May 30, 2008; and 61/039,454 filed Mar. 26, 2008,which are hereby incorporated by reference in their entirety. Thisapplication is also a continuation in part of U.S. patent applicationSer. No. 11/941,728 filed Nov. 16, 2007, which is hereby incorporated byreference in its entirety. This application is also a continuation inpart of U.S. patent application Ser. No. 12/191,834 filed Aug. 14, 2008,which is hereby incorporated by reference in its entirety. Thisapplication is also a continuation in part of U.S. patent applicationSer. No. 12/234,307 filed Sep. 19, 2008, which is hereby incorporated byreference in its entirety. This application is also a continuation inpart of U.S. patent application Ser. No. 12/234,360 filed Sep. 19, 2008.

TECHNICAL FIELD

This invention generally relates to heating systems and in particular toa heating system and method for electronic displays.

BACKGROUND OF THE ART

In a typical electronic display, heat transfer systems typically seek toremove heat from the display. This may be done in any number of ways,but usually these systems generally attempt to remove heat from theelectronic components in a display through sidewalls of the displayhousing.

When typical displays experience low temperatures, the heat transfersystem is not adapted to maintain the heat of the display, or perhapsgenerate additional heat. This may be necessary, as low temperatures cancause a display to malfunction, not display images properly, or maypermanently damage the display. Specifically for liquid crystal displays(LCDs), the crystal material may malfunction once the displayexperiences low temperatures. They crystal material may not respondappropriately to a potential difference and, in some cases, the crystalmaterial may even freeze. Furthermore, although there may be some heatnear the back of the display where the electrical components are, thisheat has no way of contacting the area near the crystal material andthus heating the crystals.

SUMMARY OF THE INVENTION

Exemplary embodiments relate to an isolated gas heating system and amethod for heating an electronic display. An exemplary embodimentincludes an isolated gas heating chamber. The gas heating chamber ispreferably a closed loop which includes a first gas chamber comprising atransparent anterior plate and a second gas chamber comprising a heatingplenum. The first gas chamber is anterior to and coextensive with theviewable face of the electronic display surface. The transparentanterior plate may be set forward of the electronic display surface byspacers defining the depth of the first gas chamber.

A heating chamber fan, or equivalent means, may be located within theheating plenum. The fan may be used to propel gas around the isolatedgas heating chamber loop. As the gas traverses the first gas chamber itcontacts the electronic display surface, transferring heat to the frontsurface of the display. Because the gas and the relevant surfaces of thefirst gas chamber are transparent, the image quality remains excellent.After the gas has traversed the transparent first gas chamber, the gasmay be directed into the rear heating plenum. In order to heat the gasin the plenum, heating elements may be used. In other embodiments,electronic components which operate the display may be placed within theheating plenum. These components naturally generate heat duringoperation, and can further heat the gas within the heating plenum. Thesecomponents will also run more efficiently, if cool air is regularlycirculated over them.

The foregoing and other features and advantages of the present inventionwill be apparent from the following more detailed description of theparticular embodiments of the invention, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of an exemplary embodiment will be obtained froma reading of the following detailed description and the accompanyingdrawings wherein identical reference characters refer to identical partsand in which:

FIG. 1 is a perspective view of an exemplary embodiment in conjunctionwith an exemplary electronic display.

FIG. 2 is an exploded perspective view of an exemplary embodimentshowing components of the isolated gas heating system.

FIG. 3 is top plan view of an exemplary embodiment of the heatingchamber.

FIG. 4 is a front perspective view of an embodiment of the isolatedheating chamber, particularly the transparent anterior surface of firstgas chamber.

FIG. 5 is a rear perspective view of an embodiment of the isolatedheating chamber, particularly the heating plenum.

FIG. 6 is a schematic of several embodiments for heating elements.

DETAILED DESCRIPTION

Exemplary embodiments provide an isolated gas heating system for anelectronic display.

FIG. 1 is an exemplary embodiment of the present invention. As may beappreciated, when the display 10 is exposed to cold temperatures and/orwind, the temperatures inside the display 10 will vary greatly withoutsome kind of heating device, and may even drop below freezing. As such,the electronics including the display screen (e.g., LCD screen) may notfunction properly and may have a greatly reduced life span. Byimplementing certain embodiments of the heating system disclosed herein,temperature fluctuation is greatly reduced.

The display shown is equipped with an innovative gas heating system.Accordingly, it may be placed in environments which may experience lowtemperatures. Although the heating system may be used on any type ofelectronic display, it is especially useful for LCD displays.

In FIG. 1, the display area of the electronic display shown includes anarrow gas chamber that is anterior to and coextensive with theelectronic display surface. Optionally, the display also may have areflection shield 119, to mitigate reflection of any sunlight on thedisplay surface. Additionally, if the display experiences very coldtemperatures, especially in outdoor environments, housing 70 may be acolor which absorbs sunlight.

It is to be understood that the spirit and scope of the disclosedembodiments includes heating of displays including, but not limited toLCDs. By way of example and not by way of limitation, the presentinvention may be used in conjunction with displays selected from amongLCD (including TFT or STN type), light emitting diode (LED), organiclight emitting diode (OLED), field emitting display (FED), cathode raytube (CRT), and plasma displays. Furthermore, embodiments of the presentinvention may be used with displays of other types including those notyet discovered. In particular, it is contemplated that the presentinvention may be well suited for use with full color, flat panel OLEDdisplays. While the embodiments described herein are well suited foroutdoor environments, they may also be appropriate for indoorapplications (e.g., factory environments, coolers, freezers, frozen foodprocessing plants) where thermal stability of the display may be atrisk.

As shown in FIG. 2 an exemplary embodiment 10 of the electronic displayand gas heating system includes an isolated gas heating chamber 20contained within an electronic display housing 70. A narrow transparentfirst gas chamber is defined by spacers 100 and transparent front plate90. A second transparent front plate 130 may be laminated to front plate90 to help prevent breakage of front plate 90. If used with a LCDdisplay, heating chamber 20 surrounds the LCD stack 80.

Referring to FIG. 3, in at least one embodiment the isolated gas heatingchamber 20 comprises a closed loop which includes a first gas chamber 30and a second gas chamber 40. The first gas chamber includes atransparent plate 90. The second gas chamber comprises a heating plenum45. The term “isolated gas” refers to the fact that the gas within theisolated gas heating chamber 20 is essentially isolated from externalair in the housing of the display. Because the first gas chamber 30 ispositioned in front of the display image, the gas should besubstantially free of dust or other contaminates that might negativelyaffect the display image. An optional air filter (not shown) may beemployed within the plenum to assist in preventing contaminates and dustfrom entering the first gas chamber 30.

The isolated gas may be almost any transparent gas, for example, normalair, nitrogen, helium, or any other transparent gas. The gas ispreferably colorless so as not to affect the image quality. Furthermore,the isolated gas heating chamber need not necessarily be hermeticallysealed from the external air. It is sufficient that the gas in thechamber is isolated to the extent that dust and contaminates may notsubstantially enter the first gas chamber.

In the closed loop configuration shown in FIG. 3, the first gas chamber30 is in gaseous communication with the second gas chamber 40. A heatingchamber fan 50 may be provided within the posterior plenum 45. Theheating fan 50 may be utilized to propel gas around the isolated gasheating chamber 20. The first gas chamber 30 includes at least one frontglass 90 mounted in front of an electronic display surface 85. In anexemplary embodiment, the electronic display surface 85 may be adjacentto a LCD stack so that heat can easily transfer to the liquid crystalmaterial. Optionally, the electronic display surface 85 may be the frontportion of the LCD stack.

Referring now to FIG. 4, the front plate 90 may be set forward from theelectronic display surface 85 by spacers 100. The spacing members 100define the depth of the narrow channel passing in front of theelectronic display surface 85. The spacing members 100 may beindependent or alternatively may be integral with some other componentof the device (e.g., integral with the front plate). The electronicdisplay surface 85, the spacing members 100, and the transparent frontplate 90 define a narrow first gas chamber 30. The chamber 30 is ingaseous communication with plenum 45 through entrance opening 110 andexit opening 120.

The posterior surface of the first gas chamber 30 preferably comprisesthe electronic display surface 85 of the display stack 80. As theisolated gas in the first gas chamber 30 traverses the display itcontacts the electronic display surface 85. Contacting the heating gasdirectly to the electronic display surface 85 allows heat to transfer tothe electronic display surface 85, and subsequently to the display stack80. Accordingly, the term “electronic display surface” may refer to thefront surface of a typical electronic display (in the absence of theembodiments disclosed herein). The term “viewable surface” or “viewingsurface” refers to that portion of the electronic display surface fromwhich the electronic display images may be viewed by the user.

The electronic display surface 85 of typical displays is glass. However,neither display surface 85, nor transparent front plate 90, nor optionalsecond transparent front plate 130 need necessarily be glass. Therefore,the term “glass” will be used herein interchangeably with the termplate. By utilizing the electronic display surface 85 as the posteriorsurface wall of the gas compartment 30, there may be fewer surfaces toimpact the visible light traveling through the display. Furthermore, thedevice will be lighter and cheaper to manufacturer.

Although the embodiment shown utilizes the electronic display surface85, certain modifications and/or coatings (e.g., anti-reflectivecoatings) may be added to the electronic display surface 85, or to othercomponents of the system in order to accommodate the heating gas or toimprove the optical performance of the device. In the embodiment shown,the electronic display surface 85 may be the front glass plate of aliquid crystal display (LCD) stack or the front plate of a plasmadisplay or the front plate of an OLED display. However, almost anydisplay surface may be suitable for embodiments of the present heatingsystem. Although not required, it is preferable to allow the heating gasin the first gas chamber 30 to contact the electronic display surface 85directly. In this way, the convective effect of the circulating gas willbe maximized. Preferably the gas, which has transferred heat to theelectronic display surface 85 may then be diverted to the heating plenum45 where it may absorb heat.

To prevent breakage, the optional second surface glass 130 may beadhered to the front surface of plate 90. Also, surface glass 130 may beheat tempered to improve its strength and may be coated with apolarizer. As shown in FIG. 3, fan 50 propels a current of air aroundthe loop (see arrows) of the isolated gas heating chamber 20.

The plenum 45 defining the second gas chamber 40 is adapted to circulatethe gas behind the electronic display assembly. Heating elements 200 maybe located within the second gas chamber 40 and operate to warm the gasas it passes through the second gas chamber 40. These heating elementscan be any one of the many commonly available heating elements. Manytimes, these elements are simply a material which contains a highelectrical resistance, and thus generates heat when current flowsthrough it. The heating elements can be, but are not limited to, any oneof the following: nichrome wire or ribbon, screen printed metal/ceramictracks deposited on ceramic insulated metal (generally steel) plates,CalRod (typically a fine coil of nichrome wire in a ceramic binder,sealed inside a tough metal shell), heat lamp, and Positive ThermalCoefficient (PTC) of resistance ceramic.

Additionally, the plenum 45 may contain electrical components 210 whichpower and control the electronic display. The electrical components maybe any one of the following: transformers, microprocessors, printedcircuit boards, resistors, capacitors, motors, wiring harnesses, andconnectors. The electrical connections for the electrical components 210may pass through a wall of the plenum 45. The electrical components 210can be located anywhere within the plenum 45. The electrical components210 may be mounted on the posterior or anterior surface of the plenumand may be mounted directly on the surface of the plenum or may besuspended by mounting posts so that gas may pass all around thecomponent.

FIG. 4 shows that the anterior surface 90 of the first gas chamber 30 istransparent and is positioned anterior to and at least coextensive witha viewable area of an electronic display surface 85. The arrows shownrepresent the movement of the isolated gas through the first gas chamber30. As shown, the isolated gas traverses the first gas chamber 30 in agenerally horizontal direction. Although heating system 20 may bedesigned to move the gas in either a horizontal or a vertical direction,it is preferable to propel the gas in a horizontal direction. In thisway, if dust or contaminates do enter the first gas chamber 30, theywill tend to fall to the bottom of chamber 30 outside of the viewablearea of the display. The system may move air left to right, oralternatively, right to left.

As is clear from FIG. 4, to maximize the heating capability of thesystem, the first gas chamber 30 preferably covers the entire viewablesurface of the electronic display surface 85. Because the relevantsurfaces of the first gas chamber 30 as well as the gas containedtherein are transparent, the image quality of the display remainsexcellent. Anti-reflective coatings may be utilized to minimize specularand diffuse reflectance. After the gas traverses the first gas chamber30 it exits through exit opening 120. Exit opening 120 defines theentrance junction into the rear heating plenum 45.

FIG. 5 shows a schematic of the rear heating plenum 45 (illustrated astransparent for explanation). One or more fans 50 within the plenum mayprovide the force necessary to move the isolated gas through theisolated gas heating chamber. Whereas the first gas chamber 30 wasdesigned to transfer heat from the gas to the front surface 85 of thedisplay, the second gas chamber 40 is designed for the gas to absorbheat from either the heating elements 200, the electrical components210, or both. Plenum 45 may have various contours and features toaccommodate the internal structures within a given electronic displayapplication.

It should be noted that two different types of heating elements areshown in the figures. However, a single type of heating element could beused in an exemplary embodiment. Alternatively, a combination ofdifferent types of heating elements could be used. Again, the specifictype of heating element is entirely dependent upon the specificapplication, costs, size of the display, and surrounding environment.Several different types of CalRod heating elements are shown in FIG. 6.Obviously, these types of heating elements can take on almost any shape,and the designs which are shown are only exemplary and are notexhaustive.

In some embodiments, it may be advantageous to insulate the plenumwalls, so that heat from the warm gas may not escape into thesurrounding environment. This may be useful in situations where thetemperature remains relatively cold throughout the operative life of thedevice, or perhaps when the display must temporarily experience verycold temperatures.

Furthermore, some electronic displays may be required to operate in abroad range of temperatures, i.e. from very hot to very cold. Thesedisplays may utilize both the heating system which is herein disclosed,as well as the cooling system disclosed in Co-pending application Nos.61/033,064, Ser. No. 12/191,834, 61/053,713, 61/057,599, and 61/039,454.These embodiments may also contain the optional air curtain device,described in Co-pending application Ser. No. 11/941,728.

In some applications, the isolated gas heating system may runcontinuously while the display is operational. However, if desired, atemperature sensor (not shown) and a switch (not shown) may beincorporated. This thermostat may be used to detect when temperatureshave reached a predetermined threshold value. In such a case, theisolated gas heating system may be selectively engaged when thetemperature in the display reaches a predetermined value. Predeterminedthresholds may be selected and the system may be kept within anacceptable temperature range.

Having shown and described preferred embodiments, those skilled in theart will realize that many variations and modifications may be made toaffect the described embodiments and still be within the scope of theclaimed invention. Additionally, many of the elements indicated abovemay be altered or replaced by different elements which will provide thesame result and fall within the spirit of the exemplary embodiments. Itis the intention, therefore, to limit the invention only as indicated bythe scope of the claims.

1. A heating system for an electronic display having a display surface, the system comprising: a first gas chamber positioned anterior to the electronic display surface; a second gas chamber in gaseous communication with said first gas chamber; a heating chamber fan within said second gas chamber to propel gas around the first and second gas chambers; and means for heating the gas contained within the second gas chamber.
 2. The system of claim 1, wherein: the first gas chamber comprises a transparent anterior plate; and the second gas chamber comprises a heating plenum.
 3. The system of claim 2, wherein the first gas chamber further comprises the electronic display surface; spacers separating the electronic display surface and said transparent anterior plate; and an entrance opening and an exit opening.
 4. The system of claim 3, wherein: the first gas chamber further comprises a second transparent anterior plate bonded to the first transparent anterior plate.
 5. The system of claim 2, wherein: the first gas chamber is adapted to transfer heat from the gas to the display surface.
 6. The system of claim 2, wherein the means for heating the gas comprises heating elements.
 7. The system of claim 1, wherein the means for heating the gas comprises electrical components.
 8. The system of claim 1, further comprising: a temperature sensing device within said first gas chamber; a switch in communication with said temperature sensing device and said heating chamber fan; and wherein the fan is switched on when the temperature within the first gas chamber reaches a threshold value.
 9. The system of claim 6 wherein the plenum is thermally insulated.
 10. The system of claim 1 wherein said fan runs continuously when the display is in operation.
 11. The system of claim 1 further comprising a filter within the second gas chamber.
 12. A heating system for an electronic display having a display surface, said system comprising: a first gas chamber comprising the display surface of the electronic display; a transparent anterior plate separated from said display surface by spacers; and an entrance and exit opening; and a second gas chamber in gaseous communication with said first gas chamber, said second gas chamber comprising a heating plenum; a heating chamber fan to propel gas around the first and second gas chambers; and one or more heating elements.
 13. The system from claim 12 further comprising one or more electrical components within the heating plenum.
 14. The system from claim 12 further comprising a filter within said second gas chamber.
 15. The system from claim 12 further comprising: a temperature sensing device within said first gas chamber; a switch in communication with said temperature sensing device and said heating chamber fan; and wherein the fan is switched on when the temperature within the first gas chamber reaches a threshold value.
 16. A method for heating an electronic display having a display surface with isolated gas, comprising the steps of: providing an isolated gas system comprising a first gas chamber which is in contact with the electronic display surface and a second gas chamber comprising a heating plenum, wherein the first and second gas chambers are in gaseous communication; forcing isolated gas into the first gas chamber; transferring heat from the isolated gas to the electronic display surface; directing the isolated gas into the heating plenum; heating the isolated gas in the plenum; and reintroducing the heated isolated gas into the first gas chamber.
 17. The method of claim 16, wherein the heating step comprises the steps of: providing one or more heating elements within said heating plenum; forcing the isolated gas over said one or more heating elements; and transferring heat from the heating elements to the isolated gas.
 18. The method of claim 16, further comprising the steps of: setting a threshold temperature for the isolated gas; measuring the temperature of the isolated gas; comparing the temperature of the isolated gas to the threshold temperature; and heating the isolated gas only when the temperature of the isolated gas is less than the threshold temperature.
 19. The method of claim 16, further comprising the step of filtering the isolated gas prior to forcing it into the first chamber.
 20. The method of claim 16, further comprising the step of preventing a substantial amount of heat from escaping the second gas chamber. 